System and method for processing commands from a plurality of control sources

• US 5,285,380 A
• Filed: 08/07/1991
• Issued: 02/08/1994
• Est. Priority Date: 08/07/1991
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Payton, David W.
• Primary Examiner(s): MacDonald, Allen R.
• Application Number:
  US07/741,880
• Time in Patent Office: 916 Days
• Field of Search: 395/51, 395/61, 395/900, 395/903, 395/905, 395/90, 395/81, 395/93, 364/174, 364/175, 364/461
• US Class Current: 700/69
• CPC Class Codes: G05B 9/03 with multiple-channel loop, i.e. redundant control systems
• CPC Class Codes: G05D 1/0077 using redundant signals or controls
• CPC Class Codes: Y10S 706/90 Fuzzy logic

Abstract

A system for obtaining collective decisions from multiple control sources. The system is able to produce a single command from these control sources. Each control source corresponds to a behavior and each responds to inputs to produce a command. The system employs a piece-wise constant preference profile composed of zones, spikes, and clamps which compress the amount of the amount of data required to process behavior preferences. The system sorts commands according to command values in a chart to produce a total profile which represents the combination of profiles of the command values for multiple behaviors. The peak zone in the total profile is then used to produce a desired response to the multiple commands. The system allows behaviors to be combined through command fusion rather than subsumption. The piece-wise constant representation allows behavior commands to be combined after they have been passed through a standard control system. This permits behaviors to use any derivative of the control source'"'"'s variable that is appropriate for their function. The system has a bounded arbitration time so that control loop stability will not be disrupted by the arbitration process. The system also incorporates a method for smoothing behavior switching transients.

Claims

1. A system for producing a single command for a controlled system from a plurality of control sources, said system comprising:

a plurality of control sources each responding to inputs to produce a command output represented as a piece-wise constant preference level profile covering a full continuous range of allowable command values;

means for representing the piece-wise constant preference level profiles in terms of attributes in order to easily combine and sort the preference level profiles to obtain a total profile within a bounded time period;

means for creating the total profile from the combination of individual preference level profiles of the plurality of control sources by adding the preference level profiles for each of the plurality of control sources;

means for determining a peak zone in said total profile having the largest preference level; and

means for producing a desired response in the controlled system to the command indicated by said peak zone.

2. The system of claim 1 further comprising means for determining the relative contribution that each of the plurality of control sources has made to the command indicated by said peak zone.

3. The system of claim 2 further comprising:

means for determining the dominant control source from said relative contribution.

4. The system of claim 3 further comprising:

means for modifying the effective activation of said dominant control source by small increments to produce sample output commands; and

means for averaging said sample commands to produce a smooth output signal, whereby oscillations between two disjoint output commands are reduced.

5. The system of claim 1 wherein said plurality of control sources includes a first control source producing a command of a first type;

a second control source producing a command of a second type, said second type being derivative of said first type command; and

wherein said system further comprises means for converting said commands of a first type into commands of said second type, whereby said system operates on commands of said second type to produce a single response to said first and second control sources.

6. The system of claim 1 wherein said preference level profiles are defined by said control sources by the upper and lower limits of zones, and by spikes corresponding to zones having single command values.

7. The system of claim 6 wherein said command values further comprise clamp regions corresponding to exclusionary commands defining zones which are not permitted, and said system further comprises means for clamping said peak zone wherein said clamp regions are excluded.

8. The system of claim 6 wherein said means for creating a total profile further comprises:

means for generating an array of preference levels at zone edges, said array being equal in size to the total number of zone edges in said preference level profiles of said control sources; and

said array containing the preference levels of each of the plurality of control sources at each zone edge as well as the sum of said preference levels at each zone edge, wherein said total profile is created from said sum.

9. The system of claim 1 wherein said control sources control the movement of a vehicle and said input to said control sources include sensors responsive to said vehicle'"'"'s location and movement.

10. A system for arbitrating multiple commands for a controlled system from a plurality of control sources, each responding to inputs to produce a command output, said system comprising:

means for generating a command output represented as a piece-wise constant preference level profile covering a full continuous range of allowable command values;

means for representing the piece-wise constant preference level profiles in terms of attributes in order to easily combine and sort the preference level profiles to obtain a total profile within a bounded time period;

means for creating the total profile from the combination of preference level profiles of the plurality of control sources by adding the preference level profiles for each of the plurality of control sources;

means for determining a peak zone in said total profile having the largest preference level; and

means for producing a desired response in the controlled system to the command indicated by said peak zone.

11. The system of claim 10 wherein said plurality of control sources includes a first control source producing a command of a first type;

a second control source producing a command of a second type, said second type being derivative of said first type command; and

wherein said system further comprises means for converting said commands of a first type into commands of said second type, whereby said system operates on said commands to the second type to produce a single response to said first and second control sources.

12. The system of claim 10 wherein said preference level profiles are defined by said control sources by the upper and lower limits of zones, and by spikes corresponding to zones having single command values.

13. The system of claim 12 wherein said command values further comprise clamp regions corresponding to exclusionary commands defining zones which are not permitted, and said system further comprises means for clamping said peak zone wherein said clamp regions are excluded.

14. The system of claim 12 wherein said means for creating a total profile further comprises:

means for generating an array of preference levels at zone edges, said array being equal in size to the total number of zone edges in said preference level profiles of said control sources; and

said array containing the preference levels of each of the plurality of control sources at each zone edge as well as the sum of said preference levels at each zone edge, wherein said total profile is created from said sum.

15. The system of claim 10 further comprising:

means for determining the level of participation of each of the plurality of control sources; and

means for determining the dominant control source from said level of participation.

16. The system of claim 15 further comprising:

means for modifying the effective activation of said dominant control source by small increments to produce sample output commands; and

means for averaging said sample commands to produce a smooth output signal, whereby oscillations between two disjoint output commands are reduced.

17. The system of claim 10 for arbitrating multiple commands for a controlled system from a plurality of control sources, each responding to inputs to produce a command output, further comprising a sensor interface unit for sampling data from a plurality of sensors, and

wherein said means for generating a command output represented as a piece-wise constant preference level profile includes a behavior central processing unit (CPU) for reading data from said sensor interface unit and generating new command data represented as piece-wise constant profiles, and

said means for representing the piece-wise constant preference level profiles includes behavior command memory for storing said piece-wise constant profile, and

said means for creating the total profile includes an arbitration CPU for analyzing command preference profiles to obtain unique command values including means for generating a table of sorted behavior comands for actuators to be controlled and a command profile memory for storing said command preference profiles, said arbitration CPU further comprising said means for determining a peak zone in said total profile having the largest preference level;

and

said means for producing a desired response in the controlled system to the command indicated by said peak zone includes an actuator interface unit for receiving unique command values generated by said arbitration CPU representing said peak command zone, and for generating signals controlling said actuators.

18. A method for arbitrating multiple commands for a controlled system from multiple behaviors, said method comprising:

providing a plurality of control sources, each responding to inputs to produce a command output represented as a piece-wise constant preference level profile, covering a full continuous range of allowable command values;

representing the piece-wise constant preference level profiles in terms of attributes in order to combine and sort the preference level profiles to obtain a total profile within a bounded time period;

creating the total profile from the combination of preference level profiles of the plurality of control sources by adding the preference level profiles for each of the plurality of control sources;

determining a peak zone in said total profile having the largest preference level; and

producing the desired response in the controlled system in response to the command indicated by said peak zone.

19. The method of claim 18 further comprising the steps of:

generating a command of a first type from a control source of a first type;

generating a command of a second type from a control source of a second type, said command of the second type being derivative of said first type command; and

converting said commands of a first type into commands of said second type, whereby said system operates on said commands of the second type to produce a single response to said first and second control sources.

20. The method of claim 18 further comprising the step of defining said preference level profiles by the upper and lower limits of zones and also by spikes corresponding to zones having single command values.

21. The method of claim 20 further comprising the steps of:

generating command values having clamp regions corresponding to exclusionary commands defining zones which are not permitted; and

clamping said peak zone wherein said clamp regions are excluded.

22. The method of claim 20 wherein said step of creating a total profile further comprises the steps of generating an array of preference levels at zone edges, said array being equal in size to the total number of zone edges in said preference level profiles of said control sources, said array containing the preference level of each of the plurality of control sources at each zone edge as well as the sum of said preference levels at each zone edge, wherein said total profile is created from said sum.

23. The method of claim 18 further comprising the steps of determining the level of participation of each of the plurality of control sources;

and

determining the dominant control source from said level of participation.

24. The method of claim 23 further comprising the steps of:

modifying the effect of activation of the dominant behavior by small increments to produce sample output commands; and

averaging said sample commands to produce a smooth output signal, whereby oscillations between two disjoint output commands are reduced.

25. A system for arbitrating multiple commands from a plurality of control sources, each responding to inputs to produce a command output, said system comprising:

sensor interface unit for sampling data from a plurality of sensors;

behavior central processing unit (CPU) for reading data from said sensor interface unit and generating new command data represented as a piecewise constant profile;

behavior command memory for storing said piecewise constant profile;

control CPU for transforming command issued by behaviors into control commands that are suitable to control actuators;

arbitration CPU for analyzing command preference profiles to obtain unique command values including means for generating a table of sorted behavior commands for actuators to be controlled;

command profile memory for storing said command preference profiles;

said arbitration CPU further comprising means for selecting a peak zone in a total preference profile;

actuator interface unit for receiving unique command values generated by said arbitration CPU representing said peak command zone, and for generating signals controlling said actuators.

26. A system for producing a single command for a controlled system from a plurality of control sources, said system comprising:

a plurality of control sources each responding to inputs to produce a command output represented as a piece-wise constant preference level profile covering a full continuous range of allowable command values;

means for representing the piece-wise constant preference level profiles in terms of attributes in order to combine and sort the preference level profiles to obtain a total profile within a bounded time period;

means for creating the total profile from the combination of individual preference level profiles obtained from the plurality of control sources, and

means for producing a desired response in the controlled system on the basis of the shape of the total profile.

27. The system of claim 26 wherein said preference level profiles are defined by said control sources by the upper and lower limits of zones, and by spikes corresponding to zones having single command values.

28. The system of claim 27 wherein said means for creating a total profile further comprises:

means for generating an array of preference levels at zone edges, said array being equal in size to the total number of zone edges in said profiles of said control sources; and

said array containing the preference levels of each said control source at each zone edge and the combination of said preference levels at each zone edge, wherein said total profile is created from said combination.